Mobile communications radio receiver for multiple network operation

ABSTRACT

A mobile communications radio receiver for multiple radio network operation includes an RF unit for generating a first down-converted signal from a radio signal received from a first radio network and a second down-converted signal from a radio signal received from a second radio network. Further, it includes a first receiver comprising a paging indicator channel demodulator for demodulating a paging indicator channel of the first radio network based on the first down-converted signal, and a second receiver including a pilot channel demodulator for demodulating a pilot channel of the second radio network based on the second down-converted signal. A first data connection is configured to couple paging information contained in the second down-converted signal to an input of the paging indicator channel demodulator of the first receiver.

FIELD

The invention relates to mobile communications, and more particularly tothe technique of receiving and processing pagings from multiplenetworks.

BACKGROUND

A new feature for receivers in mobile communications isDual-SIM-Dual-Standby (DSDS). It means the UE (user equipment) contains(at least) two SIM (subscriber identity module) cards and registers in(at least) two networks. If the UE is in an idle/standby state, it shallbe able to receive pagings, i.e. notifications of incoming calls ormessages, from both networks.

Another challenging feature for a Dual SIM (DS) phone is to receive apaging on one network during an active connection (e.g. call) on theother network. This feature will be referred to asDual-SIM-Single-Transport (DSST) in the following.

A straight-forward approach to avoid missing of a paging on one networkwhile being in a call on the other network (i.e. during a DSST scenario)is to add a second receive path to the UE. However, this meansadditional hardware, implying additional chip area and powerconsumption.

For these and other reasons there is a need for improvements intechniques for receiving and processing pagings from multiple networks.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of embodiments and are incorporated in and constitute partof this specification. The drawings illustrate embodiments and togetherwith the description serve to explain principles of embodiments. Otherembodiments and many of the intended advantages of embodiments will bereadily appreciated as they will become better understood by referenceto the following detailed description. Like reference numerals designatecorresponding similar parts.

FIG. 1 is an illustration of a first multiple network scenario for amobile communications radio receiver.

FIG. 2 is an illustration of a second multiple network scenario for amobile communications radio receiver.

FIG. 3 is block diagram illustrating an embodiment of a mobilecommunications radio receiver.

FIG. 4 is a diagram illustrating by way of example a possible structureof a paging indicator channel and a control channel associatedtherewith.

FIG. 5 is a block diagram illustrating an embodiment of a mobilecommunications radio receiver.

FIG. 6 is a block diagram illustrating an embodiment of a mobilecommunications radio receiver.

FIG. 7 is a flowchart of an embodiment of a method of listening topagings transmitted by a second network while having a connectionestablished with a first network.

FIG. 8 is a timing diagram illustrating a first scenario of continuouspacket connectivity on a first network and paging on a second network.

FIG. 9 is a timing diagram illustrating a second scenario of continuouspacket connectivity on a first network and paging on a second network.

FIG. 10 is a timing diagram illustrating a third scenario of continuouspacket connectivity on a first network and paging on a second network.

FIG. 11 is a block diagram illustrating an embodiment of a mobilecommunications radio receiver.

FIG. 12 is a flowchart of an embodiment of a method of listening topagings transmitted by a second network while having a DRX continuouspacket connection established with a first network.

FIG. 13 is an illustration of a receive diversity mobile communicationsradio receiver receiving a signal from a first network.

FIG. 14 is an illustration of a receive diversity mobile communicationsradio receiver operating in a single receiver mode on the first networkand in a paging mode on a second network.

FIG. 15 is a block diagram illustrating an embodiment of a receivediversity mobile communications radio receiver.

FIG. 16 is a flowchart of an embodiment of a method of listening topagings transmitted on a second network while operating in a singlereceiver mode on the first network.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings, which form a part thereof, and in which are shownby way of illustration specific embodiments in which the invention maybe practiced. In the drawings, like reference numerals are generallyutilized to refer to like elements throughout the description. In thefollowing description, for purposes of explanation, numerous specificdetails are set forth in order to provide a thorough understanding ofone or more aspects of embodiments of the invention. It may be evident,however, to one skilled in the art that one or more aspects of theembodiments of the invention may be practiced with a lesser degree ofthese specific details. In other instances, known structures and devicesare shown in a simplified representation in order to facilitatedescribing one or more aspects of the embodiments of the invention. Thefollowing description is therefore not to be taken in a limiting sense,and the scope of the invention is defined by the appended claims.

The various aspects summarized may be embodied in various forms. Thefollowing description shows by way of illustration various combinationsand configurations in which the aspects may be practiced. It isunderstood that the described aspects and/or embodiments are merelyexamples, and that other aspects and/or embodiments may be utilized andstructural and functional modifications may be made without departingfrom the scope of the present disclosure. In particular, it is to beunderstood that the features of the various exemplary embodimentsdescribed herein may be combined with each other, unless specificallynoted otherwise.

As employed in this specification, the terms “coupled” and/or“electrically coupled” are not meant to mean that the elements must bedirectly coupled together; intervening elements may be provided betweenthe “coupled” or “electrically coupled” elements.

The mobile communications radio receiver described herein will bereferred to as UE (user equipment) and may be employed in terminaldevices of wireless communication systems, in particular in mobilephones or other mobile terminal devices.

By way of example, FIG. 1 illustrates a first multiple network scenariofor a mobile communications radio receiver (UE). The UE is configured toregister in two networks NW1 and NW2. In this embodiment, the networksNW1 and NW2 are operated on different frequency bands f1 and f2. Thus,since the UE must be available to receive pagings from the NW1 operatorand the NW2 operator, the UE must be able to tune to frequency bands f1and f2. By way of example, as shown in FIG. 1, different base stationsB1, B2 (i.e. different cells) may be used by the networks NW1 and NW2.However, it is also possible that networks NW1 and NW2 use shared basestations B1=B2 (i.e. the same cells).

FIG. 2 illustrates a second multiple network scenario for an UE. The UEis configured to register in two networks NW1 and NW2. In contrast tothe scenario illustrated in FIG. 1, the networks NW1 and NW2 areoperated on the same frequency band f1. Thus, the UE is available toreceive pagings from the NW1 operator and the NW2 operator if tuned tofrequency band f1. By way of example, as shown in FIG. 2, different basestations B1, B2 (i.e. different cells) may be used by the networks NW1and NW2. However, it is also possible that networks NW1 and NW2 useshared base stations B1=B2 (i.e. the same cells).

Throughout this description, the signals received from the first andsecond networks NW1, NW2 are different, i.e. they contain differentinformation.

FIG. 3 is a block diagram illustrating an embodiment of an UE 100. UE100 comprises an RF unit 1, a first receiver 20 for demodulating a firstdown-converted signal S1 from a radio signal received from the firstradio network NW1 and a second receiver 30 for demodulating a seconddown-converted signal S2 from a radio signal received from the secondradio network NW2. The first receiver 20 comprises, inter alia, a pagingindicator channel demodulator 2 which may be operated to demodulate apaging indicator channel (PICH) of the first radio network NW1 based onthe first down-converted signal S1.

In this embodiment, the PICH demodulator 2 of the first receiver 20 isconnected by a data connection 4 to signal S2 which contains the pagingindicator channel signal of the second network NW2. This allows forresource sharing between the first and second receivers 20, 30. Morespecifically, during DSST, when there is an active connectionestablished on network NW1, i.e. the first receiver 20 is active todemodulate e.g. speech data of a call on network NW1, the PICH resourceof the first receiver 20 would be unused. In this situation, the signalwhich contains the paging indicator (PI) of the second network NW2 isrouted via data connection 4 to the PICH demodulator 2 of the firstreceiver 20. Thus, a paging on the second network NW2 may be detected inthe first receiver 20. Note that the second receiver 30 may be a reducedreceiver such as, e.g., implemented in a Dual-Cell/Dual-Band HSUPA (HighSpeed Uplink Packet Access) receiver, which has no PICH demodulator.

FIG. 4 is diagram illustrating by way of example a possible structure ofa PICH and a control channel associated with the PICH and referred to asSCCPCH (Secondary Common Control Physical Channel). PICH and SCCPCH areused for pagings in general WCDMA systems.

The PICH is repeatedly transmitted over radio frames having a length of,e.g., 10 ms, i.e. the length of UMTS (Universal MobileTelecommunications System) radio frames. The PICH is used to carry theP1. The PICH is always associated with an SCCPCH to which a PCH (PagingCHannel) is mapped. A PI set in a PICH frame means that a paging messageis to be transmitted on the PCH in the SCCPCH frame. There is a timedifference of T_(PICH) between the PICH frame and the SCCPCH frameassociated with the PICH frame. In other words, the SCCPCH frame istransmitted T_(PICH) after the end of the PICH frame. The time gapT_(PICH) between the PICH and SCCPCH frames may be between 2 ms (3slots) and 20 ms (30 slots).

FIG. 5 illustrates a block diagram of one embodiment of UE 100. By wayof example, the RF unit 1 may comprise two RF stages 1.1 and 1.2. The RFstages 1.1 and 1.2 may be tuned to different frequency bands. RF stage1.1 comprises an RF down-converter and provides the first down-convertedsignal 51 from a radio signal received from network NW1 and RF stage 1.2comprises an RF down-converter and provides the second down-convertedsignal S2 from a radio signal received from network NW2. Thus, differentdown-conversion frequencies may be concurrently used in the RF stages1.1 and 1.2, respectively. The RF unit 1 may in particular be used in adual cell/dual band environment using different frequency bands fortransmissions of networks NW1 and NW2 as shown in FIG. 1.

FIG. 5 further illustrates a block diagram of the first and secondreceivers 20 and 30 contained in UE 100, respectively. As mentionedearlier in conjunction with FIG. 3, the UE 100 may contain a first ormain receiver 20 and a second or reduced receiver 30. The main receiver20, which may be an UMTS Rel99 receiver, may comprise a number ofdemodulators, e.g. a CPICH (Common Pilot CHannel) demodulator 21 forpilot demodulation, a PCH(SCCPCH) demodulator 22 for PCH demodulation incase a PI is detected by the PICH demodulator 2, a second SCCPCHdemodulator 23, a PCCPCH (Primary Common Control Physical CHannel)demodulator 24, a DPCH1/FDPCH (Dedicated Physical CHannel/FractionalDedicated Physical CHannel) demodulator 25, two additional DPCHdemodulators 26, 27 and a HSUPA (High Speed Uplink Packet Access)demodulator 28 for demodulating the corresponding RGCH (Relative GrantCHannel), HICH (Hybrid ARQ Indicator CHannel) and AGCH (Absolute GrantCHannel).

The reduced receiver 30 may contain a number of demodulators which areneeded for Dual-Carrier HSUPA capability, namely a CPICH demodulator 31for pilot demodulation, a FDPCH demodulator 32 and a HSUPA demodulator33 for demodulating the corresponding RGCH, HICH and AGCH.

It is to be noted that in HSUPA uplink data is transmitted on twodifferent carriers. Thus, to receive the corresponding (different) HSUPAcontrol channels, an UE having HSUPA capability needs a second receiver.To limit semiconductor chip area and power consumption, the secondreceiver may be stripped down to the functions necessary for thedemodulation of the HSUPA control channel on the second carrier. Thereduced receiver 30 shown in FIG. 5 is such a second receiver configuredfor HSUPA control channel demodulation. Note that this reduced receiver30 may not contain any DPCH demodulator, since on the second carrier noRel99 data downlink channel DPCH exists. Further, the reduced receiver30 does not contain any PICH and/or PCH(SCCPCH) demodulators for thereceipt of pagings. This may also apply to the UE 100 illustrated inFIG. 3.

Further, the UE 100 in one embodiment may contain only one single mainreceiver 20 employing, e.g., demodulators 21 to 28 and only one singlereduced receiver 30 employing, e.g., demodulators 31 to 33.

Similar to the illustration in FIG. 3, a data connection 4 is used toroute signal S2, which contains the PICH and the SCCPCH on the secondnetwork NW2, to the main receiver 20, and, more specifically, e.g. tothe inputs of the PICH demodulator 2 and the PCH(SCCPCH) demodulator 22.Again, since the main receiver 20 is operating a call on the firstnetwork NW1 (i.e. the DSST scenario is considered), the paging resourcesin the main receiver 20 are unused. More specifically, while theDPCH1/FDPCH demodulator 25 and the DPCH2 and DPCH3 demodulators 26, 27in the main receiver 20 are used to demodulate the downlink speech datafrom network NW1, the PICH demodulator 2 and the PCH(SCCPCH) demodulator22 are configured to demodulate in parallel to the DPCH1/FDPCHdemodulator 25 and the DPCH2 and DPCH3 demodulators 26, 27 (i.e.parallel to an active call) the PICH and PCH(SCCPCH) frames on networkNW2.

The second or reduced receiver 30 may comprise a channel estimator togenerate channel estimates based on the second down-converted signal S2.Here, by way of example, the CPICH demodulator 31 may be used as achannel estimator. Thus, at an output of the CPICH demodulator 31,channel estimates indicative of the communication link over the secondnetwork NW2 are provided. These channel estimates are routed via dataconnection 5 to the first main receiver 20.

The channel estimates generated in the reduced receiver 30 and providedvia data connection 5 may be input to the PICH demodulator 2 and thePCH(SCCPCH) demodulator 22 of the main receiver 20 in order todemodulate the PI and the SCCPCH on the second carrier (second networkNW2). This is possible since these resources are unused during DSST inUE 100. When rerouting the paging information of the second network NW2to the unused PICH and PCH(SCCPCH) demodulators 2, 22 in the mainreceiver 20, the outputs of these demodulators 2, 22 have to beinterpreted by downstream paging decoder circuitry (not shown) to beindicative of pagings on the second network NW2 rather than pagings onthe first network NW1.

As known in the art, the receivers 20, 30 are also referred to as innerreceivers (IRX) and may, for instance, be implemented by a RAKEreceiver. The outputs of the various demodulators 2, 21 to 28 and 31 to33 are indicated by arrows and may be coupled to individual decoders. InFIG. 5, by way of example and for the sake of illustrative ease, only achannel decoder 40 for decoding the outputs of the DPCH1/FDPCHdemodulator 25 and the DPCH2 and DPCH3 demodulators 26, 27 is shown.Such channel decoder 40 is also referred to as outer receiver (ORX) inthe art. It is to be noted that the UE 100 may comprise a number ofchannel decoders (not shown) with each channel decoder being configuredto decode a specific channel signal received from one channeldemodulator 2, 21 to 28 of the main receiver 20 and from one channeldemodulator 31 to 33 of the reduced receiver 30.

FIG. 6 illustrates a block diagram of one embodiment of UE 200. The UE200 may comprise only one single RF unit 1, which can only be tuned toone frequency band. The RF unit 1 provides a down-converted signal whichcomprises signal S1 received from network NW1 and signal S2 receivedfrom network NW2. Thus, the same down-conversion frequency is used togenerate signals S1 and S2. The UE 200 may in particular be used in adual cell/single band environment using the same frequency band fortransmissions of networks NW1 and NW2 as shown in FIG. 2.

Further, the UE 200 may in particular be used in a dual cell/single bandenvironment operating in only one network NW1. In this case, twosubscribers corresponding to the two SIM cards may use the UE 200concurrently.

The UE 200 may comprise only a single receiver 20. Similar to theoperation already explained with respect to FIGS. 3 and 5, during anactive connection (e.g. call) on one SIM, the DPCH1/FDPCH demodulator 25and the DPCH2 and DPCH3 demodulators 26, 27 in the receiver 20 are usedto demodulate the downlink speech data for one SIM. During thisactivity, the PICH demodulator 2 and the PCH(SCCPCH) demodulator 22 areconfigured to demodulate in parallel to the DPCH1/FDPCH demodulator 25and the DPCH2 and DPCH3 demodulators 26, 27 (i.e. parallel to an activecall) any pagings received on PICH and SCCPCH for the other SIM (i.e.the other subscriber). Since on the same network the CPICH is valid forboth subscribers, a second (reduced) receiver 30 is not needed. In FIG.6, the vertical arrows indicate channel estimates generated in the CPICHdemodulator 21 to be used for demodulating pagings in the PICHdemodulator 2 and the PCH(SCCPCH) demodulator 22.

FIG. 7 is a flowchart of an embodiment of a method of listening topagings transmitted by the second network NW2. This method may beperformed by UE 100 or 200 as shown in FIGS. 3, 5 and 6.

As already described above, a first down-converted signal S1 from aradio signal received from a first radio network NW1 and a seconddown-converted signal S2 from a radio signal received from a secondradio network NW2 are generated at A1 and A2, respectively. Forinstance, as shown in FIG. 5, RF stages 1.1 and 1.2 may be used togenerate S1 and S2, respectively.

When there is no active data connection established with the firstnetwork NW1, the paging indicator channel of the first network NW1 basedon the first down-converted signal S1 is demodulated in the PICHdemodulator 2 of the main radio receiver 20 at A3. Further, thePCH(SCCPCH) demodulator 22 is used to demodulate the correspondingcontrol channel SCCPCH of the first network NW1.

When the first network NW1 is signaling via PICH and SCCPCH that aconnection is to be established, the DPCH1/FDPCH demodulator 25 and theDPCH2 and DPCH3 demodulators 26, 27 are activated to demodulate downlinkmessage data such as e.g. speech data. Thus, a connection on the firstradio network NW1 is established at A4. Then, while having an existingconnection established on the first radio network NW1, a PICH and aSCCPCH of the second radio network NW2 based on the seconddown-converted signal is demodulated at A5 in the same PICH demodulator2 and the same PCH(SCCPCH) demodulator 22 as has been used before todemodulate the corresponding PICH and SCCPCH of the first network NW1.This is accomplished by replacing the signal S1 by the signal S2 at theinputs of the PICH demodulator 2 and the PCH(SCCPCH) demodulator 22,i.e. by rerouting the signal S2 to the main receiver 20.

According to another aspect, discontinuous reception (DRX) cycles ofcontinuous packet connectivity (CPC) on the first network NW1 are usedto receive pagings from the second network NW2. FIGS. 8 to 10 are timingdiagrams illustrating various scenarios of CPC on the first network NW1and paging on the second network NW2.

With CPC an UE can have an active connection to the first network NW1,but if no data is sent the UE only checks in certain intervals if datais available. In between these checks the UE can be turned off to savepower. The intervals between the checks are referred to as CPC DRXcycles.

FIG. 8 illustrates the timing of a CPC connection between the firstnetwork NW1 and an UE. The time spans during which the UE checks whetherdata is available on the first network NW1 are indicated by C1, C2, C3,. . . , Cn, Cn+1.

Since the demodulator of the UE is turned off during the CPC DRX cyclesbetween C1, C2, C3, . . . , Cn, Cn+1, it can be turned on during theseperiods in order to listen to pagings on the second network NW2. In oneembodiment, if the second network NW2 is operated on a differentfrequency band f2 than the frequency band f1 used by the first networkNW1, see FIG. 1, the UE has to be tuned to the second frequency band f2upon activation during the CPC DRX cycles. In another embodiment, if thefirst and second networks NW1 and NW2 operate on the same frequency bandf1, see FIG. 2, the UE must not be tuned to another frequency band whenactivated during the CPC DRX cycles of the first network NW1 to listento pagings on the second network NW2.

FIG. 8 illustrates the case where there is a CPC connection but noactivity (beyond the CPC DRX cycles) on the first network NW1 and thereare no pagings on the second network NW2. The paging instances on thesecond network NW2, i.e. the times when the PI in the PICH frames mayoccur, are indicated by P1, P2, . . . . Here, the paging instances ofthe second network NW2 fit into the CPC DRX cycles of the first networkNW1 (which operates on an existing but idle CPC connection with the UE).Therefore, the occurrence of a PI at a paging instance in the secondnetwork NW2 would be detectable. Note that the paging cycle on thesecond network NW2 is defined by the time interval between consecutivepaging instances P1, P2, . . . . The duration of the paging cycle may bee.g. between 80 and 5120 ms.

It is to be noted that the paging cycle may be considerably longer thanthe CPC DRX cycle. Thus, as illustrated in FIG. 8, it may not benecessary to re-activate the UE during each CPC DRX cycle in order tolisten to pagings on the second network NW2. Rather, since the length ofthe paging cycle of network NW2 is known in the UE, it may be sufficientto activate the UE only during specific CPC DRX cycles, e.g. during thecycle between C1 and C2 and the cycle between Cn and Cn+1, see FIG. 8.

If the paging instances P1, P2 of the second network NW2 overlap withshort activities on the first network NW1 within a CPC DRX cycle tocheck for data, at least in the scenario of FIG. 1 (different frequencybands f1, f2), an UE having one RF unit 1 can not listen anymore topagings P1, P2 on the second network NW2. This situation is illustratedin FIG. 9. FIG. 9 illustrates CPC activity on the first network NW1concurrently with the timing of the paging instance P1 on the secondnetwork NW2.

In this case there are two options: The first option is that paging P1is lost because of the ongoing CPC activity on the first network NW1.Since pagings are typically repeated several times (e.g., a paging atpaging instance P1 is repeated after a delay of one paging cycle atpaging instance P2), there is a high probability to receive at least oneof the repetitions. For instance, as illustrated in FIG. 9, therepetition of paging P1 at paging instance P2 would be received becausethere is no simultaneous CPC activity in the CPC DRX cycle between Cnand Cn+1. The user probably would not notice the short delay.

The second option is to prioritize the listening to pagings on thesecond network NW2 over the short DRX CPC activities on the firstnetwork NW1. In this case the paging P1 would be received, whereas theCPC activity on the first network NW1 would be missed. However, missingone activity instance in CPC would not drop the CPC DRX connection onthe first network NW1. It probably means only a short delay in the startof a possible data transfer on the first network NW1.

Thus, depending on the priority settings, either CPC activity on thefirst network NW1 or listening to pagings on the second network NW2 maybe prioritized, and in both cases both operations could be performed(even though the non-prioritized operation may be delayed for a specifictime such as one or more CPC DRX cycles or one or more paging cycles,respectively). The priority setting (DRX CPC or paging prioritized) maybe adapted on the basis of the settings of the two networks NW1, NW2. Byway of example, the priority setting may depend on the length of thepaging cycle, the number of repetitions of pagings and/or the length ofthe CPC DRX cycle.

FIG. 10 illustrates a case of paging on the second network NW2 and noactivity (beyond the CPC DRX cycles) on the first network NW1. Here, thePICH frame is assumed to contain a paging indicator (PI) at the paginginstance P1. Therefore, as explained in conjunction with FIG. 4, the PCHis to be demodulated in the associated SCCPCH frame. In FIG. 10 the PCHis indicated by reference signs PC1, PC2, PC3.

By way of example, C2 may occur concurrently with PC1. In this case oneCPC info packet, namely the packet which would be received during C2, islost if paging on the second network NW2 is prioritized over the CPC DRXconnection on the first network NW1. This is illustrated in the leftside portion of FIG. 10.

On detecting a paging on the second network NW2, an active call on thesecond network NW2 may be set up. In this case there are two options:The first option is to stop the CPC DRX connection on the first networkNW1. In this case the CPC DRX connection is terminated. Another optionis to maintain the CPC DRX connection on the first network NW1 and toaccept packet loss in the call on the second network NW2. Since lostpackets can also occur in an uninterrupted connection, the user wouldnot notice the packet loss on the second network NW2 due to thecontinuation of the CPC DRX connection on the first network NW1. Thissituation of conflicting CPC DRX connection on the first network NW1 andan active call on the second network NW1 is depicted in the middleportion if FIG. 10 with reference to C3, C4 and P2, PC2, respectively.

As further shown in FIG. 10, it is also possible that the paginginstance P3 (PICH frame) and the corresponding PCH (referred to as PC3)on the SCCPCH frame fit into the CPC DRX cycle gap. In this case, eachpaging (PICH and PCH) can be received on the second network NW2, and noCPC DRX info packet is lost during demodulation of the pagings.

In one embodiment, not shown in FIG. 10, there is an active continuousdata transfer connection on the first network NW1. In this case it wouldtypically not be possible to listen anymore to the paging on the secondnetwork NW2, because there are no CPC DRX cycles any more. However, evenin this case, depending on the setting of the number of repetitions ofdata packets on the first network NW1 if a data packet is lost, it mighteven be possible to shortly interrupt the data transfer on the firstnetwork NW1 through higher layers (TCP/IP . . . ) and listing instead topossible pagings on the second network NW2. Listening to a pagingindicator (PI) on the second network NW2 requires only a few slots (seeFIG. 4) and much less than an UMTS frame. Therefore, even in this caseof a continuous data connection on the first network NW1, it might bepossible to shortly listen to the second network NW2 during the PIinstances P1, P2, . . . because the lost data packets on the firstnetwork NW1 will probably be repeated. Thus, the user would not noticethe loss of packets on the first network NW1 connection. Even for a longongoing data transfer on the first network NW1, the packet dropping dueto listening for pagings on the second network NW2 will only result in aslightly lower throughput on the first network NW1, which will not benoticed by the user.

FIG. 11 illustrates an embodiment of an UE 300 configured to be operatedusing one or more of the methods described above with reference to FIGS.8 to 10. This UE 300 may comprise one single receiver 20 which may besimilar to the main receiver 20 shown in FIG. 5. More specifically, thereceiver 20, which may be a UMTS Rel99 receiver, may comprise a CPICHdemodulator 21 for pilot demodulation, a PCH(SCCPCH) demodulator 22 forPCH demodulation, a second SCCPCH demodulator 23, a PCCPCH demodulator24, a DPCH1/FDPCH demodulator 25, two additional DPCH demodulators 26,27 and a HSUPA demodulator 28. The outputs of the various demodulators2, 21 to 28 are provided to a channel decoder 40 (ORX). The channeldecoder 40 may contain for each channel a respective channel decoder todecode the specific channel signal received from one channel demodulator2, 21 to 28 of the receiver 20.

The UE 300 may comprise a single-band RF unit 1, which can be tuned tothe frequency bands f1 and f2 in a sequential manner, but which can notdown-convert the frequency bands f1 and f2 concurrently. The single-bandRF unit 1 may be controlled by a control unit 50. The control unit 50 isconfigured to switch the single-band RF unit 1 to either generate thefirst down-converted signal S1 from the first network NW1 or to generatethe second down-converted signal S2 from the second network NW2. Themain receiver 20 is informed by the control unit 50 on this selection. Apriority setting in case of conflicting CPC DRX activity on network NW1and paging on network NW2 may be selected by a priority selection unit60 in accordance with the description above.

According to FIG. 12, the UE 300 may operate as follows: A firstdown-converted signal S1 from a radio signal received from a firstnetwork NW1 is generated at B1. This first down-converted signal S1 isdemodulated during a discontinuous reception instance of a CPC DRXconnection with the first radio network NW1 at B2. During a DRX cycleperiod in which no DRX instances occur, the generation of the firstdown-converted signal S1 is stopped and the second down-converted signalS2 from a radio signal received from the second network NW2 is generatedat B3. The second down-converted signal S2 is demodulated during apaging instance on the second network NW2 at B4. The control of the RFunit 1 and the receiver 20 in accordance with the above description isaccomplished by the control unit 50.

According to another aspect, receive diversity operation of an UE 400 onthe first network NW1 may be exploited to receive pagings from thesecond network NW2. FIGS. 13 and 14 are explanatory illustrations ofthis concept.

FIG. 13 illustrates an UE 400 operating in a receive diversity mode on asingle network NW1. In case of a receive diversity connection the UE 400has (at least) two antennas for receiving a first and a second radiosignal from the first network NW1. As each antenna is coupled to aseparate receiver chain in the UE 400, a receive diversity connectionoccupies two receiver chains in UE 400. In other words, the two receiverchains are tuned to the same frequency f1 and demodulate signals fromtwo different antennas containing the same information. The signals,however, are different because they arrive at the UE 400 via differentpropagation paths.

In order to receive pagings from the second network NW2, the UE 400 maybe configured to switch the receive diversity operation (FIG. 13) on thefirst network NW1 to a single receiver chain reception for the durationof the paging occurrence on the second network NW2. This releases thesecond receiver chain, which may then be used to demodulate a pagingindicator channel of the second network NW2. This is shown by way ofexample in FIG. 14. Here the receive diversity operation on the firstnetwork NW1 is interrupted and the connection on the first network NW1is continued in a single receive antenna mode, in which only onereceiver chain is needed to demodulate the radio signal (e.g. speechsignal) transmitted by the first network NW1. Concurrently, the secondreceiver chain is tuned to frequency f2 of the second network NW2. Thesecond receive antenna and the receiver chain associated with the secondantenna are then used to receive and demodulate pagings on the secondnetwork NW2.

As explained above with reference to other embodiments, the switchingfrom receive diversity operation to single antenna operation and back toreceive diversity operation requires only a few slots, because thetiming of the PI on the PICH of the second network NW2 is known in theUE 400. Therefore, although the receiver capability and the demodulationperformance on the first network NW1 are reduced for a short period oftime, the user may probably not notice this degradation. On the otherhand, he may securely receive pagings on the second network NW2.

FIG. 15 is a block diagram of an embodiment of an UE 400 configured tooperate in accordance with the description of FIGS. 13 and 14. The UE400 may comprise two antennas 60.1 and 60.2. The first antenna 60.1 iscoupled to an input of a first RF stage 1.1 of an RF unit 1, and thesecond antenna 60.2 is coupled to an input of a second RF stage 1.2thereof. The UE 400 further comprises two receiver units 20, 30.Further, the UE 400 may comprise a switch 70 with an input thereof beingcoupled to an output of the second RF stage 1.2. A first output ofswitch 70 may be coupled to an input of the first receiver unit 20 and asecond output of the switch may be coupled to an input of the secondreceiver unit 30. The first receiver unit 20 is configured to demodulateand decode two antenna signals during receive diversity operation. Thefirst and second RF stages 1.1, 1.2, the first and second receiver units20, 30 and the switch 70 are controlled by a control unit 50.

During receive diversity operation on the first network NW1 (see FIG.13), the switch 70 is controlled by the control unit 50 to couple theoutput of the second RF stage 1.2 to an input of the first receiver unit20. Thus, during e.g. an ongoing call on the first network NW1, bothantenna signals S1 and S2 are demodulated in the first receiver unit 20.At paging instance P1, i.e. the time where a PI may occur on the PICH ofthe second network NW2, the control unit 50 tunes the second RF stage1.2 to frequency f2 and operates the switch 70 to couple the output ofthe second RF stage 1.2 to an input of the second receiver unit 30.Further, the control unit 50 controls the second receiver unit 30 todemodulate and decode the PICH and, if a PI is detected on PICH, thecorresponding SCCPCH frame on the second network NW2. Thus, the firstdown-converted signal S1 associated with the first antenna 60.1 andcontaining information of e.g. the ongoing call (or another dataconnection) on the first network NW1 is demodulated in a non-receivediversity mode in the first receiver unit 20, and the seconddown-converted signal S2 associated with the second antenna 60.2 and nowcontaining the PICH of the second network NW2 is concurrentlydemodulated by the second receiver unit 30. If no PI is detected at thepaging instance, the control unit 50 controls the RF stage 1.2, theswitch 70 and the first receiver unit 20 to re-tune to the frequencyband f1, to route the output of the second RF stage 1.2 to the firstreceiver unit 20 and to re-demodulate the downlink channel on the firstnetwork NW1 in the receive diversity mode, respectively. In other words,the second receiver chain (RF stage 1.2 and second receiver unit 30) isreleased and normal receive diversity operation as shown in FIG. 13 isresumed.

Thus, the control unit 50 may be configured to control the first andsecond RF stages 1.1, 1.2 to generate the first down-converted signal S1from the radio signal received at the first antenna 60.1 by using afirst down-conversion frequency and to generate the seconddown-converted signal S2 from the radio signal received at the secondantenna 60.2 by using a second down-conversion frequency. In the receivediversity mode, the first and second down-conversion frequencies areequal. In the non-receive diversity mode, the first and seconddown-conversion frequencies are different.

According to FIG. 16, the UE 400 may operate as follows: First, at C1,the UE 400 may be operated in a receive diversity mode to demodulate asignal received at the first antenna 60.1 and a signal received at thesecond antenna 60.2. Both signals are from the first radio network NW1and contain the same information, e.g. speech information. Then, at C2,the UE 400 may be operated in a non-receive diversity mode to stilldemodulate the signal received at the first antenna 60.1 from the firstnetwork NW1 and to demodulate a signal received at the second antenna60.2 from the second network NW2. This signal received at the secondantenna 60.2 from the second network NW2 contains different informationthan the signal received at the first antenna 60.1 from the firstnetwork NW1. When operated in the non-receive diversity mode, the secondreceiver unit 30 may demodulate a paging indicator channel of the secondnetwork NW2 from the signal received at the second antenna 60.2.

It is to be noted that the reception of speech or data and parallelpaging reading as described above in all embodiments can be done in anyRAT (Radio Access Technology) receivers. By way of example, in case of a3G and 2G connection, each receiver chain may receive separately thecorresponding 2G and 3G paging information. Thus, the first network NW1and/or the second network NW2 may each be a 2G network, a 3G network ore.g. a LTE network, and any combinations of such different networks arefeasible.

The methods, aspects and embodiments described herein all relate to DSSTscenarios, where one connection to a subscriber (e.g. of a first networkNW1) is established while listening to pagings for another subscriber(e.g. of a second network NW2). Further, also a combination andinteraction with other types of Dual-SIM capabilities, for instance DSDS(Dual-SIM-Dual-Standby), where both receiver chains are in a standbymode (i.e. with no active connection on any one of the networks NW1,NW2), or DSDT (Dual-SIM-Dual-Transport), where both receiver chainsprocess an active connection to a first and second network NW1 and NW2,respectively, are possible. Further, the methods, aspects andembodiments described herein can be extended to three or more networksand/or they can be combined.

Further, it is to be noted that in all aspects and embodiments describedherein, the UEs 100 to 400 may be configured for using HSDPH and HSUPA.

In addition, while a particular feature or aspect of an embodiment ofthe invention may have been disclosed with respect to only one ofseveral implementations, such feature or aspect may be combined with oneor more other features or aspects of the other implementations as may bedesired and advantageous for any given or particular application. Thisapplication is intended to cover any adaptations or variations of thespecific embodiments discussed herein, and the invention is intended tobe limited only by the claims and the equivalence thereof.

What is claimed is:
 1. A mobile communications radio receiver formultiple radio network operation, comprising: an RF unit configured togenerate a first down-converted signal from a radio signal received froma first radio network and a second down-converted signal from a radiosignal received from a second radio network, wherein the first radionetwork and the second radio network are different radio networks; afirst receiving unit comprising a paging indicator channel demodulatorconfigured to demodulate a paging indicator channel of the first radionetwork based on the first down-converted signal; a second receivingunit comprising a pilot channel demodulator configured to demodulate apilot channel of the second radio network based on the seconddown-converted signal, wherein the second receiving unit does notcomprise a paging indicator channel demodulator configured to demodulatea paging indicator channel of the second radio network; and a first dataconnection configured to couple paging information contained in thesecond down-converted signal to an input of the paging indicator channeldemodulator of the first receiving unit, wherein the paging indicatorchannel demodulator of the first receiving unit is configured todemodulate the paging indicator channel of the first radio network andthe paging indicator channel of the second radio network.
 2. The mobilecommunications radio receiver of claim 1, further comprising: a channelestimator configured to generate channel estimates based on the seconddown-converted signal; and a second data connection configured to couplethe channel estimates to an input of the first receiving unit.
 3. Themobile communications radio receiver of claim 2, wherein the channelestimator comprises the pilot channel demodulator contained in thesecond receiving unit.
 4. The mobile communications radio receiver ofclaim 2, wherein the second data connection is configured to couple thechannel estimates to an input of the paging indicator channeldemodulator of the first receiving unit.
 5. The mobile communicationsradio receiver of claim 1, wherein the RF unit comprises: a first RFdown-converter for generating the first down-converted signal; and asecond RF down-converter for generating the second down-convertedsignal.
 6. The mobile communications radio receiver of claim 1, whereinthe mobile communications radio receiver is an HSUPA receiver.
 7. Themobile communications radio receiver of claim 1, wherein the radiosignal received from the first radio network and the radio signalreceived from the second radio network contain different information. 8.A method of demodulating pagings in a mobile communications radioreceiver, comprising: generating a first down-converted signal from aradio signal received from a first radio network; generating a seconddown-converted signal from a radio signal received from a second radionetwork, wherein the first radio network and the second radio networkare different radio networks; demodulating a paging indicator channel ofthe first radio network based on the first down-converted signal in apaging indicator channel demodulator of a radio receiver; establishing aconnection on the first radio network and demodulating downlink data ofthe first down-converted signal; and during the existing connection onthe first radio network, when the paging channel indicator demodulatoris unused to demodulate the paging indicator channel of the first radionetwork, routing the second down-converted signal to the pagingindicator channel demodulator of the radio receiver to demodulate apaging indicator channel of the second radio network based on the seconddown-converted signal in the paging indicator channel demodulator of theradio receiver.
 9. The method of claim 8, further comprising: generatingchannel estimates based on the second down-converted signal; andcoupling the channel estimates to an input of the paging indicatorchannel demodulator when demodulating the paging indicator channel ofthe second radio network based on the second down-converted signal. 10.The method of claim 8, wherein the first down-converted signal isgenerated from the radio signal received from the first radio network byusing a first down-conversion frequency, the second down-convertedsignal is generated from the radio signal received from the second radionetwork by using a second down-conversion frequency, and the first andsecond down-conversion frequencies are different.
 11. The method ofclaim 8, wherein the radio signal received from the first radio networkand the radio signal received from the second radio network containdifferent information.